Loans and Allowance for Credit Losses - Nonaccrual and Past Due Greater than 90 Days (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	$ 70,970	$ 61,605
Financing Receivable, 90 Days or More Past Due, Still Accruing	1,990	1,615
Financing Receivable, Nonaccrual, No Allowance	27,986
Commercial real estate- owner occupied
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	11,324	11,654
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual, No Allowance	4,465
Commercial real estate- Non-owner occupied
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	9,376	7,173
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual, No Allowance	6,425
Consumer real estate – mortgage
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	26,106	24,667
Financing Receivable, 90 Days or More Past Due, Still Accruing	517	168
Financing Receivable, Nonaccrual, No Allowance	379
Construction and land development
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	2,390	2,278
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual, No Allowance	1,287
Commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	21,716	15,685
Financing Receivable, 90 Days or More Past Due, Still Accruing	1,089	946
Financing Receivable, Nonaccrual, No Allowance	15,430
Consumer and other
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans	58	148
Financing Receivable, 90 Days or More Past Due, Still Accruing	384	$ 501
Financing Receivable, Nonaccrual, No Allowance	$ 0